At present, work is underway to compile a radiometric identifier of metals and alloys. For each crystalline substance a characteristic X-ray diagram is determined. The study of X-ray images allows identifying the same substances and distinguishing between dissimilar ones. The very process of determining substances consists in obtaining and calculating X-ray images and then comparing the results with previously taken reference X-ray images of known substances. The totality of reference X-ray radiographs of metals and alloys and will constitute the X-ray determinant of metals and alloys.